1. Field of the Invention
This invention relates to separation devices and more specifically, to non-contaminating separation devices.
Separation devices are used when it is desired to effect a separation of two structures that were previously adjoined to one another. Such devices typically join the structures to be separated but are later severed to release the structures from one another. A linear explosive charge, such as a mild detonating fuse, is disposed along the separation line, which may be designed to have a vulnerability to the detonation of the fuse. When separation is desired, the fuse is detonated, rupturing the device and thus allowing the structures to separate. A common application for such a separation device is in the aerospace industry, for the separation of rocket stages or for the release of payloads from cargo holds.
2. Related Art
U.S. Pat. No. 3,486,410 to Drexelius et. al., dated Dec. 30, 1969, discloses a conventional separation device comprising an expansion member comprising a detonating cord 18 disposed within a containment tube 22 where it is retained therein by support member 20. The expansion member is disposed about the perimeter of a panel 12 (FIG. 1) that is to be jettisoned from structure 10 by severing the panel therefrom along a groove 62. The explosive detonating cord is coupled to a detonator through a threaded coupling, so that it is necessary that a threaded member 50 be sealably attached to tube 22. Further, an end booster is connected to the end of cord 18 (column 4, lines 17-38). The initiator also contains an explosive detonator 42 that includes a bridge wire, whereby the detonator is electrically initiated. The containment tube has a conventionally flattened configuration so that detonation of the cord therein causes pronounced expansion of the tube in a sideways direction. Upon detonation of cord 18, the expansion member expands, fracturing panel 12 along groove 62 due to the sideways expansion resulting from detonation.
It is also known in the art to join an expansion member to an initiating device through the use of a detonation manifold. The manifold has initiation ports within which an initiating device is disposed and has flanges for receiving the ends of the containment tube and for disposing the detonation charge or fuse of the expansion member in detonation signal communication with the initiation device. The flange has a bore that communicates with the initiation port where the initiation device may be disposed. The detonation charge of the expansion member may be inserted into the flange bore so that it comes into detonation transfer relation with the initiation device. Conventionally, the flange is dimensioned and configured to have a circular external cross-sectional configuration. Accordingly, to engage the containment tube to the flange, it is necessary to flare the end of the tube significantly from its original flattened configuration to a circular configuration. Flaring the tube to this degree introduces significant stresses into the tube which may result in fractures upon detonation. The tube is then crimped circumferentially about the flange in a roll crimp procedure. It is further necessary to secure the circular crimps with retaining bands to assure that the crimps will not be undone upon detonation of the cord.
Accordingly, there is a need for a way to couple expansion tubes to detonation manifolds that result in less stress to the containment tube and, preferably, that is easier to accomplish than conventional means.